Device for feeding a fluid to a rotating machine part

Abstract

The device for feeding a fluid to a rotating machine part (6), in particular a machine tool spindle, has a housing (1) arranged to be fixed against rotation and a hollow shaft (2) mounted rotatably therein, one end of which, the inner end (2a) is connected by way of a sliding ring seal (5) to an inlet duct (4) in the housing (1). At the other, the outer, end (2b) of the hollow shaft (2, 2') there is provided a coupling tube (7, 7') coaxial with the hollow shaft and which is axially slidable with respect to the rotating machine part (6) and can be engaged with it with a sealing arrangement (8) interposed.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. In a device for feeding a fluid to a fluid receiving opening in a rotating machine part, said device including a housing arranged fixed against rotation and a hollow shaft mounted rotatably in said housing, one end of said hollow shaft being connected by way of a sliding ring seal member to an inlet duct in said housing and the other end of said hollow shaft being adapted to be connected to the rotating machine part in order to permit a flow of fluid under pressure between said housing through said hollow shaft and the rotating machine part, the improvement wherein a coupling tube is provided, said coupling tube being coaxially mounted on said hollow shaft and fixed against relative rotation with respect thereto, said coupling tube being axially slidable with respect to said hollow shaft and extending axially beyond an axial end of said hollow shaft, a return spring for providing a spring force which resists one direction of relative movement between said coupling tube and said hollow shaft, means defining a fluid inlet in said hollow shaft for receiving pressurized fluid therein from said inlet duct, said coupling tube and said hollow shaft including means responsive to a supply of said pressurized fluid to said fluid inlet means for urging said coupling tube and said hollow shaft axially with respect to each other to cause said coupling tube to move towards the rotating machine part in opposition to the force of said return spring and into engagement with the fluid receiving opening in the rotating machine part, wherein a sealing means is provided for effecting a fluid tight seal of said coupling tube to the fluid receiving opening in the rotatable machine part so and can be engaged with this machine part with a sealing arrangement interposed, that, in operation with fluid, said coupling tube will be engaged with the machine part by axial movement towards it under the pressure of the fluid to supply said pressurized fluid through said coupling tube to said rotating machine part and, in operation without fluid, be disengaged from the machine part by axial movement away from it under the force of said return spring. 
     
     
       2. The device according to claim 1, wherein a free end of said coupling tube has an extension which can be pushed into the fluid receiving opening in the rotating machine part. 
     
     
       3. The device according to claim 2, wherein said extension is cylindrical. 
     
     
       4. The device according to claim 3, wherein said extension is adjoined by a frustoconical portion which can be pressed against a corresponding frustoconical surface in the rotating machine part in the engaged position. 
     
     
       5. The device according to claim 2, wherein said sealing means includes at least one O-ring seal surrounding said extension in the engaged position thereof in the fluid receiving opening. 
     
     
       6. The device according to claim 1, wherein an overflow tube is axially slidable in said coupling tube, an outer end of said overflow tube projecting from said extension of said coupling tube and an inner end of said overflow tube bearing against a spring-loaded valve body urged closed by a spring and in a direction of fluid flow, and wherein at least one overflow opening is provided in said overflow tube in the vicinity of said inner end, so that during a major part of the movement of said coupling tube towards the rotating machine part, the valve body bears against a valve seat therefor and is moved away from the valve seat by said inner end of said overflow tube only when said outer end of said overflow tube abuts against a shoulder in the fluid receiving opening of the rotating machine part. 
     
     
       7. The device according to claim 1, wherein a stop valve opening in a direction of flow of the fluid in opposition to the force of a biasing spring is arranged in said coupling tube. 
     
     
       8. The device according to claim 1, wherein said coupling tube has at a free end thereof a sleeve which can be pushed over a corresponding extension on the rotating machine part. 
     
     
       9. In a device for feeding a fluid to a fluid receiving opening in a rotating machine part, said device including a housing arranged fixed against rotation and a hollow shaft mounted rotatably in said housing, one end of said hollow shaft being connected by way of a sliding ring seal member to an inlet duct in said housing and the other end of said hollow shaft being adapted to be connected to the rotating machine part in order to permit a flow of fluid under pressure between said housing through said hollow shaft and the rotating machine part, the improvement wherein a coupling tube is provided, said coupling tube being coaxially mounted on said hollow shaft and connected fixedly to and extending axially beyond an axial end of said hollow shaft, support means for supporting said housing for movement axially with respect to the rotating machine part, a servomotor for effecting movement of said housing and said coupling tube towards the rotating machine part, and into engagement with the fluid receiving opening in the rotating machine part, wherein a sealing means is provided for effecting a fluid tight seal of said coupling tube to the fluid receiving opening in the rotatable machine part so that, in operation with fluid, said coupling tube will be engaged with the machine part by axial movement of said housing towards the latter to supply said pressurized fluid through said coupling tube to said rotating machines part and, in operation without fluid, be disengaged from the machine part by axial movement of the housing away from it. 
     
     
       10. The device according to claim 9, wherein said servomotor is a piston and cylinder unit. 
     
     
       11. The device according to claim 10, wherein said piston is an annular piston, and wherein said cylinder unit concentrically surrounds said housing, said annular piston being slidable in said cylinder unit. 
     
     
       12. The device according to claim 9, wherein a free end of said coupling tube has an extension which can be pushed into the fluid receiving opening in the rotating machine part. 
     
     
       13. The device according to claim 12, wherein said extension is cylindrical. 
     
     
       14. The device according to claim 12, wherein said sealing means includes at least one O-ring seal surrounding said extension in the engaged position thereof in the fluid receiving opening. 
     
     
       15. The device according to claim 13, wherein said extension is adjoined by a frustoconical portion which can be pressed against a corresponding frustoconical surface in the rotating machine part in the engaged position. 
     
     
       16. The device according to claim 9, wherein said coupling tube has at a free end thereof a sleeve which can be pushed over a corresponding extension on the rotating machine part.